BIND
BIND ("BIND is not D&D") is a grunge-fantasy game about criminals, cretins, and scum guarding the civilized world from monsters, and then selling the bodies for money.
The books are made on a PiY basis ('print it yourself'), and the PDFs are free to download from the BIND website. The PDFs are not formatted for reading on a screen, so without printing they can be difficult to read.
BIND is released under a GNU General Public License 3, which permits anyone to copy, modify, or even resell the work. It also helps people work together on the game, since everyone has equal ownership. You can download the source files to compile the book yourself from Gitlab.
Setting
Fenestra is a world, built on a single question.
How would normal people actually live in a world of wandering monsters?
In the myriad walled baileys, archers guard the fields and the farmers during daylight. When night comes, people bar their doors, as large predators crawl across their rooves, and feel over the little house for an opening. Fenestra has no plagues, no famine, and war is rare. Death comes mostly from the wandering monsters.
And someone has to guard the barrier between civilization and the predators in the dark. Someone has to walk with the traders from the baileys to the town.